package com.tsmti.core.util;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.multipart.MultipartFile;

/**
 * @Package：com.tsmti.core.util
 * @Class：PoiUtil
 * @Description： POI工具类，读取excel
 * @Author：yuzh
 * @Date：Created in 2018/9/6 10:50
 * @Company:
 * @Version：
 * @Modified By:
 */
public class ReadExcelUtil {
    private static final Logger logger = LoggerFactory.getLogger(ReadExcelUtil.class);
    private final static String XLS = "xls";
    private final static String XLSX = "xlsx";

    /**
     * 读入excel文件，解析后返回
     * @param file 文件
     * @throws IOException 抛出异常
     */
    public static List<String[]> readExcel(MultipartFile file) throws IOException{
        /*检查文件*/
        checkFile(file);
        /*获得Workbook工作薄对象*/
        Workbook workbook = getWorkBook(file);
        /*创建返回对象，把每行中的值作为一个数组，所有行作为一个集合返回*/
        List<String[]> list = new ArrayList<String[]>();
        if(workbook != null){
            for(int sheetNum = 0;sheetNum < workbook.getNumberOfSheets();sheetNum++){
                /*获得当前sheet工作表*/
                Sheet sheet = workbook.getSheetAt(sheetNum);
                if(sheet == null){
                    continue;
                }
                /*获得当前sheet的开始行*/
                int firstRowNum  = sheet.getFirstRowNum();
                /*获得当前sheet的结束行*/
                int lastRowNum = sheet.getLastRowNum();
                /*循环除了第一行的所有行*/
                for(int rowNum = firstRowNum+1;rowNum <= lastRowNum;rowNum++){
                    /*获得当前行*/
                    Row row = sheet.getRow(rowNum);
                    if(row == null){
                        continue;
                    }
                    /*获得当前行的开始列*/
                    int firstCellNum = row.getFirstCellNum();
                    /*获得当前行的列数*/
                    int lastCellNum = row.getPhysicalNumberOfCells();
                    String[] cells = new String[row.getPhysicalNumberOfCells()];
                    /*循环当前行*/
                    for(int cellNum = firstCellNum; cellNum < lastCellNum;cellNum++){
                        Cell cell = row.getCell(cellNum);
                        cells[cellNum] = getCellValue(cell);
                    }
                    list.add(cells);
                }
            }
            workbook.close();
        }
        return list;
    }

    /**
     * 验证excel文件
     * @param file 文件
     * @throws IOException 异常
     */
    private static void checkFile(MultipartFile file) throws IOException{
        /*判断文件是否存在*/
        if(null == file){
            logger.error("文件不存在！");
            throw new FileNotFoundException("文件不存在！");
        }
        /*获得文件名*/
        String fileName = file.getOriginalFilename();
        /*判断文件是否是excel文件*/
        if(!fileName.endsWith(XLS) && !fileName.endsWith(XLSX)){
            logger.error(fileName + "不是excel文件");
            throw new IOException(fileName + "不是excel文件");
        }
    }

    /**
     * 获取工作簿
     * @param file 文件
     */
    private static Workbook getWorkBook(MultipartFile file) {
        /*获得文件名*/
        String fileName = file.getOriginalFilename();
        /*创建Workbook工作薄对象，表示整个excel*/
        Workbook workbook = null;
        try {
            /*获取excel文件的io流*/
            InputStream is = file.getInputStream();
            /*根据文件后缀名不同(xls和xlsx)获得不同的Workbook实现类对象*/
            if(fileName.endsWith(XLS)){
                /*xls,2003*/
                workbook = new HSSFWorkbook(is);
            }else if(fileName.endsWith(XLSX)){
                /*xlsx,2007*/
                workbook = new XSSFWorkbook(is);
            }
        } catch (IOException e) {
            logger.info(e.getMessage());
        }
        return workbook;
    }

    private static String getCellValue(Cell cell){
        String cellValue = "";
        if(cell == null){
            return cellValue;
        }
        /*把数字当成String来读，避免出现1读成1.0的情况*/
        if(cell.getCellType() == Cell.CELL_TYPE_NUMERIC){
            cell.setCellType(Cell.CELL_TYPE_STRING);
        }
        /*判断数据的类型*/
        switch (cell.getCellType()){
            /*数字*/
            case Cell.CELL_TYPE_NUMERIC:
                cellValue = String.valueOf(cell.getNumericCellValue());
                break;
            /*字符串*/
            case Cell.CELL_TYPE_STRING:
                cellValue = String.valueOf(cell.getStringCellValue());
                break;
            /*Boolean*/
            case Cell.CELL_TYPE_BOOLEAN:
                cellValue = String.valueOf(cell.getBooleanCellValue());
                break;
            /*公式*/
            case Cell.CELL_TYPE_FORMULA:
                cellValue = String.valueOf(cell.getCellFormula());
                break;
            /*空值*/
            case Cell.CELL_TYPE_BLANK:
                cellValue = "";
                break;
            /*故障*/
            case Cell.CELL_TYPE_ERROR:
                cellValue = "非法字符";
                break;
            default:
                cellValue = "未知类型";
                break;
        }
        return cellValue;
    }
}